<?php
abstract class Person1  {
    public abstract function test();
}

abstract class Person extends Person1 {
//    public function eat() {
//        echo 'eating';
//    }
    public abstract function eat($food = 'rice');

}


class Student extends Person {
    public function eat($food = 'rice')
    {
        echo 'student eating';
    }
    public function test()
    {
        // TODO: Implement test() method.
    }
}

class Worker extends Person {
    public function eat($food = 'beef') {
        echo 'worker eating ' . $food;
    }
    public function test()
    {
        // TODO: Implement test() method.
        echo 'abcd';
    }
}

$w = new Worker();
$w->test();
